Hydraulic pressure booster



INVENTOR. albert S. Kw:

2 SHEETS-SHEET l A s KUX HYDRAULIC PRESSURE BOOSTER Flled July 22, 1948 Aug. 26, 1952 A. s. KUX 2,503,059

- HYDRAULIC PRESSURE BOOSTER I Filed July 22, 1948 v 2 SHEETS-SHEET 2 INVENTOR. albert 6. Kwt

Patented Aug. 26, 1952 I II-UNITED STATES PATENT OFF HYDRAULIC PRESSUREv BOOSTER Albert S. Kux, Chicago, Ill., assignor to Kux Machine Company, Chicago, 111., a corporation of Illinois Application July 22, 1948, Serial No. 40,039

i to hydraulic pressure apply [pressure in two successive stages on the injection plunger in injectin the molten metal in a mold, the secondary application of'pressure following immediately the first, but being intensified or multiplied during a portion of the final travel of the plunger stroke.

Another object of my invention is the pro-; vision of a device of the foregoing character in which the travel of the piston rod is extended or continued after the secondary application of pressure, so that when the device is used in connection'with the operation of a die casting machine, as above described, the piston rod will act to eject the slug or sprue of chilled metal from the mold.

'A further object of my invention is the provision of a device of the character set forth which is self contained and which is fully automatic in its operation.

- Other'and further objects of my invention will be apparent from the following description taken in connection with'the accompanying drawings inwhich: I

--Fig. 1 is a vertical sectional'view of a device embodying'my invention, in one of its positions. 7

Fig.2 is'a horizontal cross sectional view of the casing along the longitudinal axis of the valve cylinder bore, the section being taken substantially ;on line 2'-2 of Fig. 1.

Fig. 3 is a verticalsectional view taken substantially on'line 3-3 of Fig. 2. e a

-Fig. '4 isa similar view taken substantially on line 4-4 of Fig. 2..-

Referring to the drawings wherein is shown a preferred embodiment of my invention, the numeral I designates generally a casing in which is formed a cylinder having a high pressure bore ll andanenlarged lowpressure bore 12 in axial alinement with av differential piston indicated operating 2 Claims. (01. 60 54.5)

generally by [3 reciprocating therein. The casing [0 is provided at one end with a member l4 secured thereto influidtightirelationship. At the other end of the casing and also secured d with cylinder bore l 2 thereto in similar fluid cylinder casing indicated generally by l6 and hereinafter to be described in which a piston :11

and piston rod I8 are arranged to reciprocate;

Formed in the casing'lilbelow the'c'ylinders II and i2 is a valve cylinder having] bores 19} reciprocating and 20 in which arereceived for H d movement a spool valve indicated generally by 2|. inlet po-rt 22 connected to a conduit 25, and exhaust port 23 connected to cit-'- haust conduit 30, andcommunicates with the cylinder'bore H throu'gh passages 24 and 26 {and with cylinder bore l2 through passages 21 and 28, the latter being formed in the end member IL.

The valve cylinder bores 19 and 20 communicate and 32, and the bore haust port 23 through passages 33, 3!, and 32.

The end member [4 is provided with a bore axially alined with the cylinder'bores Hand I24" The bore 36 communicates with cylinder bore H l as; check through passage 31, exterior piping valve 39 and passage 4|. that pressure gages may piping circuit at points 40a andlflb to register the pressures in cylinder bores II and I2 at any particular timeof operation.

The differential piston I 3 comprises a high pressure piston head 42 and an integral enlarged low pressure piston head It will be understood 1 The spool valve 2| head 46 receivable in bore 20, and a body portion in receivablein beingprovided with annular recesses'48 and 50. The spool valve 21 is length to receive acompressing spring 5|, the tension vofthe spring being adjustable by means of a square headed threaded stem 52 in threaded engagement with end member I4 and having a shoulder 53 which engages one end ofthe said spring. Aswill' be apparent; the springnormally urges the spool valve to theleft from the posi tion seenin Fig. '1. 5 i

The cylinder casing portion having a'bore with bores H and 12. N 16' through which the 'piston rod 54 in coaxial alinement gland 51. The casing pressure fluid supply contight relationship is; a"

The valve cylinder bore I9 is provided I pressure fluid supply I2 through passages 29, 3i; [2 communicates with exbe connected into the l 43 reciprocable in cylf mder bores II and I2 respectively. integrally formed with the piston head 43 in coaxial aline= griient is a plug valve 44 reciprocable in the bore is provided with an enlarged bore [9, the said body-portion" :bored for a portion of its 16 comprises a tubular The portion of the casing V I8 extends is sealed by packing 56 confined by a packing,

duit 59 which communicates with cylinder bore 54 through passages BI and 62. A conduit 63 provides communication between passage GI and cylinder bore 20. The casing i6 is provided with a plugged vent 64 which communicates with cylinder bore 54, the vent serving to exhaust any air that may be trapped in the cylinder bore 54.

The piston. H and piston rod l8 are suitably secured together in rigid relationship and recivalve not shown connected to conduits 25: and

59 and to a suitable pump, although any other suitable means for controlling theflow of hydraulic fluid may be used. I

The operation of the device will now be described: I

Fig. l. of the drawings shows the device; about tobe'ginla power stroke to the right. Previously pressure fluid h ad been admitted into conduit 53; the said fluid passing through passages BI and 62 into bore 54 to move piston 11 to theright, the said fluid also passing through passage 63= into bore 20 to act onvalve head 46 to move the same to the position illustrated in Fig. 1. A four-way valve is actuated to admit hydraulic fluid under,

pressure through conduit 25 into port 22, the fluid flowing through bore [9 and recess 48 of valve,2.l, through passages 24 and 26 into cylinder bore H. 'When pressure fluid is being admitted into conduit-25the'four way'valve acts-to restrict the return flowv of fluid in conduit 59. Under. the conditions mentioned the piston I l and piston rod I8..proceed to move to the left, thefiuid in cylinder bore 54 being caused to pass into pase.

sa es fil andfil and into conduit 59. Also, this fiuidwill transmit pressure through the fluid in conduit63 and in the cylinder bore 20 on piston l1. Thus, the secondary application of pressure by piston l1 follows immediately the first, but is intensified or multiplied to a desired degree during a portion of the final travel of the stroke of the piston.

It will be seen in the travel of differential piston l3 that so long as plug 44 is disposed within the bore 36, the port to passage}?is'closed and pressure fluid can act only on piston head 43'; However, the length of travel of piston IS in the bore I2 is greater than the length of plug 44. Con- V sequently, during the final travel of piston l3 the 'plug 44 is withdrawn completely from the bore 36 thereby opening said bore to pressure fiuidwhich enters cylinder l2 and also uncovering the port to passage 31. Pressure fluid then passes-through passage 31, piping 38, check valve '39 and into cylinder bore II where it acts on piston I] to cause the same to travel farther to 46 .maintainingthe valve 2| inthe position illus trated in Fig. 1 sothat pressure fluid may. con.-

tinue to flow 'as above described into cylinder bore! l. 7

When a predetermined resistanceto the; travel of the piston I1 takes place duringthe primary application of pressure by the piston l1, when.

as in the caseofa die casting operation the metal is. forced'into the molduntil the. surface hardening of the molten metal stops the further advance of the. piston, a reductionin backpressureacting on the valve head 46 resulting from'the arrestingof motion of piston I1 and the continued discharge or draining of fluid through passagesil and 62 relieves the pressure in conduit 63; and.

cylinder bore 20 and thereby causes-the spring biasedvalve 2] to moveto the left. The flow of pressure fluid into passage 24 isfltherebyshut off and admitted into passages 21" and" 28: and the right end of cylinder bore l2. Under the conditionslmentioned, the difierential piston, [3 'pro-. ceed'sfto move to the leftand, through the medium. of the hydraulic fluid confined inthefbore ll and-in the communicating passages such as. 26

and, transmits thetotal force actingontheenlarged piston head 43 to the head of piston l1 which has a smaller circular surface area than that of piston head 43, thereby multiplying, the

unitflpressureon the head of pistonl] by the ratio, of circular; areas ofpiston headjiand piston.

d mu at n w eonduit: 3o

In orderto efiect return movement of thepis ion rod 1 ,1 flowof ui i ers d by. 4 1 .181?- tion ofa four-way valve; and; pressure fipid ep ters into conduit 59-from which it passes throng}; pa s g 6 d 1 to: v i desl ore 5.4. and; through conduit Grime-cylinder; bore; 20;; The. fluid acting on the left hand -face qfi piston H; causes it to travel to the right.;, Pressure; applied to piston l1 is transmitted through the fl nfi n y nd r: piston; he d: 412 to cause-piston l3 to moveto the'right; In; t course of such moveme nt fluid incylindenl2; at;- theright side of piston 43; is drajned through pas a es v e' ihpas aee .35; .=bor ei.3,-l:.- a Passage e xhaustcpnduit 30...; lso: someof the fluid is;foreed;into passagefiithrough; piping 38 and check valve 39 into bore, l l-;, Sig. m a o s W thth r turn wemcntmf-niston l'l, pressure. fluid; passing; from; 6.1, through conduit 53' into bore 2Q acts; on; the valve head 46 and causes the'spool valve Zl;,.tQ:- .mQue-j to the right, thereby conditioning; the; parts; so

that when the four-way valve isz, again operated.

is repeated.

It will beapparent;fromihe; f0regoing:.description. that Ihave provideda self COIIEElIILQd'TdGV'iCGi.

automatically operable;- to ap ly,- pressure, in two successive stages, a primary applicationpfarelaa tively lower, pressure during; the first: portion; of travel of the piston rod a'nd a-secondary applic'aza.

tion o f a' relatively higher pressure during a portion of the final travel thereof, the latteriapplica tion of pressure beingmultiplie'di-and off nitude several,times;that ofi the former Ad tion'ally, the device is automatically-operableto providean extended travel .of the-piston rod-after the secondary application. of pressure. 'It' willalso be apparent that. thetransition f-roin the lower pressure to high'eri pressure cycle:. is not determined :by any particulargposition-of the-pis ton l I. v in its travel; but" rather: determined by;

a change of pressure-im-the-pres'sure fluid wliich" occurs when the piston rod meets a force resisting its travel.

I claim:

1. A self contained unitary structure of the type described comprising a housing having a relatively large cylinder bore and a communicating relatively small cylinder bore, a unitary differential piston having two diameters and arranged for reciprocation in corresponding cylinders, a second piston disposed in a cylinder communicating with said small cylinder and adapted to be activated by fluid under pressure, said second piston being constantly spaced from said differential piston by a fluid column, said housing having a valve cylinder therein and having ports communicating with ports in said-large and small cylinders and with pressure fluid supply means, a spring biased spool valve member longitudinally shiftable in said valve cylinder for controlling the actuation of said differential and said second piston and operable to first direct pressure fluid to act on said second piston for a portion of its travel and then automatically operable, upon said piston encountering a predetermined restraining force. to direct pressure fluid to the large cylinder for actuating the piston therein thereby to transmit through the medium of the fluid confined between said second piston and the small diameter of said differential piston a force of increased intensity during the next portion of travel of said second piston, and valve means including a cylindrical extension on said large diameter piston, said extension adapted to be slidably receivable in an end cylinder communicating with said large cylinder, a conduit connecting said end cylinder with said small cylinder, said extension for a portion of the travel of said differential piston closing communication between said large cylinder and said small cylinder, but at the end of its travel opening affording communication through said conduit whereby pressure fluid is directed therethrough to said small cylinder to act on said second piston for the completion of its stroke.

2. A self contained unitary structure of the type described comprising a housing having a relatively large cylinder bore and a communicating relatively small cylinder bode, a unitary differential piston having two diameters and arranged for reciprocation in corresponding cylinders, a second piston disposed in a cylinder communicating with said small cylinder and adapted to be activated by fluid under pressure said second piston being constantly spaced from said differential piston by a fluid column, said housing having a valve cylinder therein and having ports communicating with ports in said large and small cylinders and with pressure fluid supply means, a spring biased'spool valve member longitudinally shiftable in said valve cylinder for controlling the actuation of said differential and said second piston and operable to first direct pressure fluid to act on said second piston for a portion of its travel and then automatically operable, upon said second piston encountering a predetermined restraining force, to direct pressure fluid to the large cylinder for actuating the piston therein thereby to transmit through the medium of the fluid confined between said second piston and the small diameter of said differential piston a force of increased intensity during the next portion of travel of said second piston, and valve means within said housing and operable by the travel of said differential piston to direct pressure fluid to act on said second piston for the final portion of its travel.

ALBERT S. KUX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

